The goal of ecumenism is the union of the Church. I have great hope for Catholic-Orthodox ecumenism simply because it’s possible. A group of Patriarchs could get together with a group of Bishops, sign a sheet of paper, and declare unity. The following week, the parishioners would gather and mass would continue the same as it did the week before.
I have no hope or Catholic-Protestant ecumenism because neither can hold that the other is a Church. As I’ve said before, a right thinking Protestant can believe it’s possible for a situation to arise under which he would have to leave his denomination; but a right thinking Catholic can never believe this. Again, an orthodox Catholic believes that the Church of Christ is, was and will always be identified with a single denomination; but a Protestant can never believe this- for to do so would destroy the possibility of Protestantism. These ways of seeing the Church are fundamentally contrary, which is to say they are the maximum difference within a single genus. It is precisely this contrariety makes it always possible for people to say “look at how much Catholics and Protestants have in common!”
Again, I stress that this contrariety is essential to Protestantism and Catholicism. When a Catholic walks into a Protestant religious service and discerns that everyone there is more or less equal, his natural reaction is to say “Why do I have to be here?” In other words, this is what a Catholic understands as a devotional service, and such a service can be had at home, or on a Tuesday, or once a month, or with friends, or even not at all. When a Protestant walks into a Catholic religious service and discerns that everyone there is not equal, but the priest is distinctively more important, his reaction is to say “Why does he have to be here?” The Protestant mind sees a cleric as a man put between God and other men, and as therefore, at best, a useless addition to the Gospel (this strikes me as true even in the case of High-Church Anglicans).
This was the sense of the crack that I made a few days ago about Catholic-Protestant ecumenism being like an odd dinner party, etc. All sides are waiting for the death of the other because in one way or another they realize that there can never be one Church composed of, say, Catholic and Protestant “rites”. It’s impossible even to speak of how one would form one Church from both. We can of course be polite and cordial with each other, and even learn a few things, but we will never be one and we all know it.
I say this not to be a naysayer, but in an ecumenical spirit. The discussions between Catholics and Protestants will lead to the realization that the split between them is grounded on a principles that neither side can concede without ceasing to exist. Ecumenism can be sobering too, and this is one such moment. What is called for is not more cheerful dialogue, painstaking agreements, and then calls for more study. In this particular case, an action for the unity of the Church demands that we choose the correct side, reject the other, and then dedicate our efforts toward bringing people to it.